Stop knitr note on CRAN

[bburns632]

CRAN checks often add this note:

checking dependencies in R code ... NOTE
Namespace in Imports field not imported from: ‘knitr’
  All declared Imports should be used.

This addition, which is legitimately used within the vignette eventually, should stop these messages.

It's a minor issue.

[codecov-io]

Codecov Report

Merging #168 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #168   +/-   ##
=======================================
  Coverage   84.69%   84.69%           
=======================================
  Files          10       10           
  Lines         915      915           
=======================================
  Hits          775      775           
  Misses        140      140

Impacted Files	Coverage Δ
R/CreatePackageReport.R	98.24% <ø> (ø)	⬆️

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[jameslamb]

This one is so weird! I asked about this in #119 and then it mysteriously disappeared

[jameslamb]

I did double-check the logs on Travis (I thought there was a chance we'd get like a 'opt_chunks imported but not used' thing) and looks good! 0/0/0

good fix, Brian